Fire extinguishing system for sanding machine



Sept; I, 1964 lA.15;.vlES-3CAS 3,146,558

FIRE EXTINGUI-SHING SYSTEM FOR SANDING MACHINE Filed` July 5, 1962 United States Patent C) 3,146,558 FIRE EXTINGUISHNG SYSTEM FR SANDING MACHINE Arthur l5. Vieseas, Sheihy, Ohio, assignor to American lgflachine 8L Foundry Company, a corporation of New ersey Filed July 5, 1962, Ser. No. 207,504 1 Claim. (Cl. 51-174) This invention relates to sanding machines and cornprises a fire extinguishing system provided in such a machine.

In a large, high powered floor sanding machine considerable heat is generated and the fine dust of a licor material such as Wood may, of course, be highly combustible if mixed with a sufficient amount of air. This dust is typically collected and drawn away from the cutting area by a suction system including a bag for receiving the accummulation of dust. Because of the heat generated there is always the possibility and fear that the dust will become self-ignited somewhere in the suction system and develop into a large fire. This possibility is increased, however, especially where the floor surface being sanded is of a special type which has been treated with highly combustible finishes and dressings. A typical example is bowling lanes, which are sanded by large machines and relinished periodically. When the highly combustible agents in these finishes and dressings become entrained with wood dust and a high temperature is reached, the danger of ignition is definitely present.

Accordingly, it is the main object of the invention to reduce the lire hazard involved in the sanding of certain iloor surfaces such as bowling lanes. In accordance with the invention this is accomplished by the provision of a sanding machine having an automatic lire extinguishing system incorporated therein. Briefly, this system comprises a thermal detector associated with the suction system to signal a burning condition and a source of fire extinguishing agent connected to the suction system and operable upon the signaling of such condition.

Specific details of the invention will be understood from the following description, read in conjunction with the accompanying drawings in which:

FIGURE 1 is a side elevation of an overall sanding machine embodying a system according to the invention; and

FIGURE 2 is a diagram illustrating the controls involved in the fire extinguishing system.

The sanding machine shown in FIGURE 1 has a main frame 2 which is Supported on driving wheels 4 and on caster rollers 6 at the rear of the machine. Forwardly, the machine carries a wide driving drum 8, a cutting or pressure drum 10 and an idler drum 12, with a wide abrasive belt 14 being trained about these drums. The ne dust which is created by the sanding operation is drawn off by an intake 16 which is connected to a blower 1S by a duct 20. From the blower 18 the dust is conveyed to a dust bag 22 by way of a duct 24.

A tank 30 containing a pressurized fire extinguishing agent, such as carbon dioxide, is mounted in brackets secured to the framework associated with the machine operators handle bars. Tank 30 is connected to the inlet box 28, of the bag 22, by a conduit 26. At the entrance of conduit 26 to box 28, a diffusion nozzle (not shown) preferably is employed. The release of lire extinguishing agent from the tank 30 is regulated by a solenoid valve 32 which may be operated either manually or electrically. Normally, of course (i.e. in the absence of a hazardous lire condition existing in the suction system) the valve 32 is maintained in closed position.

Referring to FIGURE 2, there is shown the general control system for the iire extinguishing means. In the inlet box 28 there is provided a thermal detector unit 36, which may employ conventional sensing means such as a thermistor or thermocouple. A unit such as indicated at 36 is entirely conventional and commercially available, being sold for example underl the Fenwal trademark. Unit 36 is set to conduct current when a higher than a predetermined temperature exists. For present purposes, it has been determined that a triggering temperature of F. is preferred. In series with thermal detector unit 36 is a coil of the normally closed solenoid valve 36, whereby valve 32 will be energized and opened upon the attainment of a temperature higher than 160 F. In parallel with the coil of valve 32, and also controlled by the thermal detector unit 36, are a buzzer 38 and a warning light 4t). In conclusion, therefore, the operation of this system is such that if a predetermined maximum temperature is reached in the suction system, indicating a condition in which ignition could occur, a valve 32 would be opened and simultaneously therewith warning signals will be emitted by the buzzer 38 and warning light 40.

A modification of the above described system may comprise the manual operation of the valve 32 by the machine operator in response to his being warned by either the buzzer 3S or the light 40. Also, one or the other of the buzzer 38 and light 40 may be dispensed with if desired.

It will be understood that various departures from the specifically disclosed embodiment of the invention may be eiiected without departing from the scope thereof as defined by the following claim:

What is claimed is:

In a sanding machine, a travelling abrasive member; a dust removal system including a duct through which dust created by said member is withdrawn and a container connected to said duct for receiving said dust; a pressurized source of lire extinguishing agent; a conduit connecting said source to said system to release lire extinguishing agent directly into the system; means for controlling said release of fire extinguishing agent into the dust removal system; and means governing the operation of said controlling means including a thermal detector located within said system, said detector being responsive to a temperature in said system exceeding a predetermined maximum to eliect the release of fire extinguishing agent directly into said system.

References Cited in the le of this patent UNITED STATES PATENTS 1,804,523 Wolfe et al. May 12, 1931 2,867,281 Donehue Ian. 6, 1959 3,040,815 Pambello lune 26, 1962 

